Where nic0 to nicN are your nic's (the "all" or "default" parameters do not apply to nic's that already exist when the sysctl settings are applied).

After a reboot, at the latest, Privacy Extensions should be enabled.

Neighbor discovery

Pinging the multicast address ff02::1 results in all hosts in link-local scope responding. An interface has to be specified. With a ping to the multicast address ff02::2 only routers will respond.

$ ping6 ff02::1%eth0

If you add an option -I your-global-ipv6, link-local hosts will respond with their link-global scope addresses. The interface can be omitted in this case.

$ ping6 -I 2001:4f8:fff6::21 ff02::1

Static address

Sometime using static address can improve security. For example, if your local router uses Neighbor Discovery or radvd (RFC 2461), your interface will automatically be assigned an address based its MAC address (using IPv6's Stateless Autoconfiguration). This may be less than ideal for security since it allows a system to be tracked even if the network portion of the IP address changes.

To assign a static IP address using netctl, look at the example profile in /etc/netctl/examples/ethernet-static. The following lines are important:

otherwise there could be some connection errors because hosts are resolved to their IPv6 address which is not reachable.

Other programs

Disabling IPv6 functionality in the kernel does not prevent other programs from trying to use IPv6. In most cases, this is completely harmless, but if you find yourself having issues with that program, you should consult the program's manual pages for a way to disable that functionality.

For example, dhcpcd will continue to harmlessly attempt to perform IPv6 router solicitation. To disable this, as stated in the dhcpcd.conf man page, add the following to /etc/dhcpcd.conf: